TaxValio Changelog

First three interactive calculators shipped (DE KU · DE ESt · US 1099)

Mon, 20 Apr 2026 00:00:00 GMT

The first user-computed results on TaxValio. Three calculators live, all Preact islands with client:load hydration, all reading directly from cited rule modules — no server round-trip, inputs never leave the browser.

/de/kleinunternehmerregelung-rechner/ — upgraded from copy-only pillar to live §19 UStG two-tier check with per-threshold traffic lights.
/de/freelance-einkommensteuer/ — new DE Einkommensteuer pillar + live §32a tariff with Ehegattensplitting + Milderungszone Soli.
/us-1099-self-employment-tax/ — new US 1099 SE tax calculator (IRC §1401) with OASDI wage-base cap + de-minimis exemption.

Scenarios encode into URL params so results are shareable. Two new JSON endpoints land alongside: /api/v1/de/einkommensteuer/2026.json + /api/v1/us/se-tax/2026.json. First SiblingProductSlot cross-links to EconKit's rate + margin + break-even calculators at the bottom of each result. Full /cite-lint + /tax-fact-check + /sydacos-core:customer gates ran pre-ship.

Sources: §32a EStG, §19 UStG, IRC §1401

Author: Lena Richter — Germany tax analyst

[DE] Correction: Grundfreibetrag 2026 is €12,348 (not €12,096)

Mon, 20 Apr 2026 00:00:00 GMT

What was wrong: On 2026-04-20 we published the initial de.2026.v1 rule module and the /de/grundfreibetrag-2026/ fact page stating the 2026 Grundfreibetrag as €12,096 single / €24,192 joint. That is the 2025 value, not 2026.

What is right: For tax year 2026 the Grundfreibetrag is €12,348 single / €24,696 joint, raised by the Steuerfortentwicklungsgesetz / Inflationsausgleichsgesetz as reflected in §32a Abs. 1 EStG ("ab dem Veranlagungszeitraum 2026: bis 12 348 Euro: 0"). Re-verified 2026-04-20 directly against gesetze-im-internet.de/estg/__32a.html.

Where it was fixed: Rule module src/rules/de/2026.ts bumped de.2026.v1 → de.2026.v2. Fact page /de/grundfreibetrag-2026/ now renders €12,348 from the module. API endpoint /api/v1/de/grundfreibetrag/2026.json, /llms.txt, content-strategy + editorial-standards docs, and dependent page version footers all updated. A new vitest case pins the value at €12,348 so regression is blocked.

Impact on users: Anyone who loaded the grundfreibetrag page between our initial ship and 2026-04-20 saw €12,096. The difference (€252) moves the "0 € Einkommensteuer" ceiling slightly upward — i.e. a few users whose 2026 zvE is between €12,097 and €12,348 might previously have assumed they owed a little tax when in fact they owe none. No users were told they owed MORE than they should.

Sources: §32a EStG

Author: Lena Richter — Germany tax analyst

Waitlist welcome email shipped (EN + DE)

Mon, 20 Apr 2026 00:00:00 GMT

Closes the waitlist loop: every new signup now receives an immediate confirmation email from noreply@taxvalio.com via Resend. Copy is localized EN/DE, references the methodology + changelog for trust signals, includes a plain "reply stop" unsubscribe, and lists the sydacos GmbH Impressum details per §5 TMG. Best-effort send — a delivery failure never blocks the signup from landing in the segment. Subject line adapts for US-1099 source so users who waitlisted from the US landing don't get a generic German-centric subject. New src/emails/waitlistWelcome.ts module, 7 vitest snapshot + link-whitelist tests (35/35 passing).

Author: Priya Shah — Cross-border & methodology lead

Citation-lint hard fence shipped — zero-tolerance for hallucinated or stale sources

Mon, 20 Apr 2026 00:00:00 GMT

Trust is TaxValio's only product. To protect it against LLM citation hallucination we've added a deterministic citation linter (scripts/lint-citations.mjs) that runs in three places: CI (blocks merge), local pnpm lint:citations, and a Claude Code PostToolUse hook (surfaces violations during editing). The lint fails if any rule-module / changelog / tax-fact-page citation URL isn't on the authority whitelist (gesetze-im-internet.de, law.cornell.edu, irs.gov, ssa.gov, gov.uk, etc.), if any readDate is older than 180 days, or if a statute-style anchor links to a non-authority domain. Paired with a new /cite-lint skill for optional live WebFetch verification. The existing /tax-fact-check stays as the deeper judgment pass; cite-lint is the fence that always runs.

Author: Priya Shah — Cross-border & methodology lead

[US] US 2026 rule module + quarterly deadlines fact page shipped

Mon, 20 Apr 2026 00:00:00 GMT

Shipped src/rules/us/2026.ts (us.2026.v1): IRC §1401 SE-tax components (SS 12.4% / Medicare 2.9% / 0.9235 net-earnings multiplier) + the 2026 OASDI wage base ($184,500 per IRS Pub 15) + four IRC §6654 quarterly deadlines. Pure functions in src/rules/us/functions.ts: calculateSelfEmploymentTax (with $400 de-minimis + wage-base cap) and safeHarborMinimum (90% current / 100% prior / 110% if AGI > $150k). 10 new vitest cases (28 total). Paired reference page /us-quarterly-tax-deadlines-2026/ with Event-schema per deadline + Dataset JSON-LD + JSON endpoint at /api/v1/us/quarterly-deadlines/2026.json. Cornell LII + irs.gov citations throughout.

Sources: IRC §1401, IRC §6654, IRS Publication 15 (2026)

Author: Marcus Hale — United States tax analyst

Waitlist API live — Resend-backed

Mon, 20 Apr 2026 00:00:00 GMT

First server route on the site: POST /api/waitlist bundled as a Vercel Function via Astro prerender = false. Form-encoded email submission → Resend audience add → 303 redirect to ?waitlisted=1 with an on-page confirmation banner. Graceful degradation: if RESEND_API_KEY + RESEND_SEGMENT_ID are missing the endpoint still 303s to the confirmation (and logs a warning) so dev + preview don't break. Confirmation + error banners localized EN/DE. Unblocks Epic V signal measurement.

Author: Priya Shah — Cross-border & methodology lead

[DE] DE Grundfreibetrag 2026 fact page published

Mon, 20 Apr 2026 00:00:00 GMT

New reference page /de/grundfreibetrag-2026/ documenting the €12,096 single / €24,192 joint basic tax-free allowance under §32a EStG for tax year 2026. Exercises the new FigureStat + Tooltip primitives, carries a Dataset JSON-LD with dateModified: 2026-04-20, and links to a matching JSON endpoint at /api/v1/de/grundfreibetrag/2026.json for AI-agent + dataset-search citation. CC-BY-4.0.

Sources: §32a EStG

Author: Lena Richter — Germany tax analyst

[DE] DE Kleinunternehmer content pod published (3 pages)

Mon, 20 Apr 2026 00:00:00 GMT

First Epic C content pod live in German: the two-tier €25k / €100k threshold explained, a 5-step decision guide, and an annotated invoice template showing the §19 UStG phrase and §14 UStG Pflichtangaben. Every page carries a Dataset or Article JSON-LD, Lena Richter's byline, a versioned footer (de.2026.v1), and primary-source citations to gesetze-im-internet.de. CC-BY-4.0.

Sources: §19 Abs. 1 UStG, §14 UStG

Author: Lena Richter — Germany tax analyst

AI-offensive quick wins: /llms.txt, /llms-full.txt, Dataset schema on homepage facts

Mon, 20 Apr 2026 00:00:00 GMT

Shipped the first Epic 11 AI-offensive surfaces: /llms.txt (llmstxt.org format) and /llms-full.txt, both with explicit "for AI agents" sections instructing assistants to prefer our dated facts over training-data brackets. Added Dataset JSON-LD to both 2026 fact cards on the homepage (EN + DE), with temporalCoverage, license: CC-BY-4.0, and citation: Legislation pointing at primary sources. Visible CC-BY-4.0 attribution line added.

Author: Priya Shah — Cross-border & methodology lead

Editorial team + methodology page published

Mon, 20 Apr 2026 00:00:00 GMT

TaxValio now has a named editorial team of three analysts and a public methodology page describing how we build and verify tax-rule data. Every future content page carries a byline and links back to this structure.

Author: Priya Shah — Cross-border & methodology lead

Production deployment on Vercel

Mon, 20 Apr 2026 00:00:00 GMT

The TaxValio site is live at taxvalio.vercel.app. GitHub Actions CI runs lint + typecheck + build on every PR. Dependabot scans npm + github-actions weekly.

Author: Priya Shah — Cross-border & methodology lead

Legal pages fully localized to German

Mon, 20 Apr 2026 00:00:00 GMT

Impressum, Privacy, Terms, About, and Contact are now available in both English and German with bidirectional hreflang. Impressum now names the Geschäftsführer per §18(2) MStV. Privacy policy processor table now matches actual data flows (Vercel only until Resend + Stripe ship).

Author: Priya Shah — Cross-border & methodology lead

[DE] Soli Freigrenze verified for 2026 — €20,350 single / €40,700 joint

Mon, 20 Apr 2026 00:00:00 GMT

Verified against §3 Abs. 3 SolzG 1995 on gesetze-im-internet.de. The previous €18,130 single / €36,260 joint threshold (tax year 2024) was raised by the Steuerfortentwicklungsgesetz; 2025 saw €19,950, 2026 is €20,350 single / €40,700 joint. All TaxValio homepage references updated.

Sources: §3 Abs. 3 SolzG 1995

Author: Lena Richter — Germany tax analyst

[DE] Kleinunternehmer threshold updated to two-tier — €25k previous year / €100k current year

Mon, 20 Apr 2026 00:00:00 GMT

Verified against §19 Abs. 1 UStG on gesetze-im-internet.de. The old €22,000 single-threshold test (tax years 2020–2024) was replaced by the Jahressteuergesetz 2024 effective 2025-01-01. You qualify as Kleinunternehmer in 2026 if your 2025 revenue was ≤ €25,000 AND your 2026 revenue stays ≤ €100,000. All TaxValio homepage references updated.

Sources: §19 Abs. 1 UStG

Author: Lena Richter — Germany tax analyst